The hospital in Nordmøre and Romsdal is a COWI's project that uses thermal energy on a large scale. Illustration: Arkitema and Ratio.

The future of heating and cooling in large buildings

Sustainability and reliability are the primary focus areas when COWI’s experts in heat pumps and cooling design thermal energy systems for future buildings.

In 1987, the release of the report ‘Our Common Future’ by the United Nations’ World Commission on Environment and Development introduced the term sustainable development and brought it onto the agenda. The Commission, led by Norwegian Prime Minister Gro Harlem Brundtland, also became known as the Brundtland Commission. 

The Brundtland Commission’s message was clear: “Development must meet the needs of the present without compromising the ability of future generations to meet their own needs.” In other words, the report emphasised the importance of the resources we use and how much we use them.

Today, carbon emissions continue to increase. According to the 2023 UN climate report, climate change is happening faster than anticipated, and the world is not on track to meet the goals of the Paris Agreement. 

Norway’s ambitious CO2 goal

In Gro Harlem Brundtland’s home country of Norway, the goal is to become a low-emission society by 2050 by reducing carbon emissions by 90-95% compared to 1990. Achieving this goal requires maximising energy efficiency in the utilisation of energy for heating and cooling buildings while increasing the production of renewable electricity.

The buildings industry holds both a great need and a great potential for sustainability. Taking Norway as an example, approximately 40% of the country’s carbon emissions stem from the buildings industry, and annual investments in new buildings amount to more than EUR 1.3 billion. 

Heat pump system. Photo: Sykehusbygg.

Sustainability in every piece of the puzzle 

COWI is currently involved in building a new 60,000 m² emergency hospital located in Hjelset, Norway, between Molde and Kristiansund. COWI is responsible for all engineering disciplines in the detailed design of the somatic building, as well as the premise-setting disciplines, building technology, automation and electronic security for the psychiatric building.

When building a new hospital, the government’s objective to reduce carbon emissions is just one of the many considerations. Hence, the design process for new hospital projects is becoming more rigorous, with higher demands on its requirements.

Designing heating and cooling systems for hospital buildings is a large and complex task. For mechanical engineers, the creative design process primarily revolves around identifying the most energy-efficient and sustainable solutions, all while ensuring that the systems can deliver the required actual efficiency. 

A heat pump utilizes ambient heat from sources such as outside air, rock, seawater or fresh water, and converts it into heat energy for heating. By supplying electrical energy, it achieves a coefficient of performance (COP) of between 3 to 5, which corresponds to 65 % to 80 % energy saving compared to direct electrical heating. 

Maximum energy efficiency … 

By conducting proper and regular maintenance, today’s heating and cooling systems have a long lifespan while maintaining consistent energy efficiency. Additionally, using eco-friendly refrigerants and high-quality components and units plays a crucial role in minimising harmful emissions to the air, soil and water.

COWI has designed a comprehensive solution at Hjelset Hospital for space heating, ventilation air heating, hot water production, space cooling and process cooling. The thermal energy plant consists of an advanced seawater-based heat pump and cooling system. Relying on high-quality, energy-efficient equipment, the heat pump and cooling system only uses eco-friendly, natural refrigerants. This contributes to good operational characteristics, significant energy savings and a prolonged lifespan.

Illustration of the hospital in Nordmøre and Romsdal: Arkitema.

… and maximum sustainability

The hospital’s energy plant is equipped with high-efficiency heat pumps that utilise heat absorption and free cooling from pumped seawater. With a focus on sustainability, the design integrates system solutions, control strategies and specified technical equipment to achieve a high proportion of renewable energy for both heating and cooling production. This includes the recovery of cooling energy, high energy efficiency, energy-optimised control and the use of only natural and eco-friendly refrigerants such as ammonia, CO₂ and propane in heat pump, cooling and refrigeration systems. Additionally, the use of high-quality equipment is prioritised, ensuring long lifespans.

The energy plant has also implemented innovative solutions to increase the share of renewable energy and energy efficiency. With a capacity of 910 kW, the heat pump system uses ammonia as a refrigerant, making it the most energy-efficient technology for this specific application.

For the peak load system, a 2,000-kW boiler system is used, powered by renewable bio-oil (in comparison, a large electric heater for a living room has a capacity of 1 to 2 kW). The cooling demand will be met by free cooling from heat pump operation and seawater. A 90-kW heat pump system using CO₂ as the refrigerant will effectively meet the demand for hot water production. The energy plant also features a 400-kW emergency cooling system consisting of water-cooled chillers using propane as the refrigerant. The refrigeration systems for cold storage and freezing use the natural refrigerants CO₂ and propane. 

Basic design of a heat pump that utilizes ambient heat (outside air, rock, seawater or fresh water) as a heat source and delivers heat to a heating system at the desired temperature. 

Back to nature’s own resources

Like most parts of Western Europe, Norway has historically relied on fossil fuels such as oil and gas to meet its thermal energy needs. Additionally, synthetic refrigerants have been commonly used in heat pumps and cooling systems. However, as the awareness of environmental challenges and climate change continues to grow, so does the awareness of alternative and more sustainable thermal energy sources. This will play a significant role in the transition towards a more sustainable society.

The greatest threat to the environment comes from the extraction and use of natural resources. Although considerable knowledge about renewable solutions existed long before the release of the 1987 Brundtland report, the market for these alternatives was not sufficiently developed. Today, we have extensive knowledge, available technology and, most importantly, a strong commitment to prioritise sustainability and the environment. In recent years, there has been significant progress in heat pump and cooling technology. As part of the effort to reduce carbon emissions, synthetic refrigerants are being phased out by 2030.

As environmental awareness becomes increasingly prevalent in today’s world, there is a growing concern about the use of synthetic refrigerants, especially hydrofluorocarbons (HFCs), due to their profound impact on the climate. In Europe, this concern has led to a drastic shift in the heat pump and cooling system industry. According to the EU’s F-gas Regulation, the harmful HFC refrigerants are to be phased out by 2030. 

An emerging global tendency

Although there is no complete global overview, it is clear that a global trend is emerging. The EU regulation has led to an increase in the use of natural alternatives such as propane, CO₂ and ammonia. Norway stands out as a prominent example of this shift, where many heat pump and cooling systems now use these more eco-friendly alternatives. This trend is also seen in other parts of Europe, where manufacturers have embraced the use of natural refrigerants.

In the United States, however, progress is slower. The environmental requirements are not as strict as those in Europe, and several manufacturers continue to use synthetic refrigerants. Nevertheless, there is a gradual transition towards natural refrigerants. 

In Asia, countries like Japan, China and India are taking the lead in implementing systems using natural refrigerants. These nations are actively working towards replacing synthetic refrigerants with more suitable alternatives. 

The transition towards natural refrigerants represents more than just a technological shift. It reflects a commitment to preserving the planet. By embracing more eco-friendly alternatives in heat pump and cooling technology, the global community is moving towards a more sustainable future. 

Choosing solutions based on local conditions

COWI has long had a clear strategy for the use of natural refrigerants in heat pumps, cooling systems and refrigeration systems. Part of the job involves ensuring the implementation of high-quality systems with the required specifications. This requires adapting the solutions to suit the local conditions. The most common sources of sustainable thermal energy supply are heat pumps using various heat sources (ground, water and outdoor air), biomass, solar energy and waste.

Local conditions can vary, making the most suitable solutions differ from one project to another. While established technical solutions may be suitable for certain projects, innovative technologies may be more suitable in others, depending on the local conditions. One of the most important tasks of HVAC consultants at COWI is to assess the local framework conditions and determine the technical solutions that provide the most optimal energy efficiency and sustainable outcomes.